i think the problem with 3ds development is that the system was a different kind of beast. compared to other platforms, it was cheap to develop for, but it was also specialized (two screens, 3d feature), and probably not very easy to make a port for. if you isolate the 3ds fanbase at the time as being between 20-30 million worldwide and then look at ps3/360/ps4/xb1 as a userbase, then making 'one game' is a lot easier across those platforms, especially as disc prices make for a lower platform charge and you can get away with a higher msrp (the only ones who dared to dream on 3ds were atlus, god bless them).
as long as porting to switch isn't a big issue, then ports should happen on the regular. maybe not for every major game, but seeing smaller stuff already announced is a good sign - nights of azure 2 and fate extella are exactly the kinds of games you would see on a platform that is getting a wide variety of support out of japan, where even the niche stuff can succeed.
the biggest problem outside of planning for a switch version of a game from the onset is the platform charge. cartridges are expensive and if you are developing a project with a certain profit margin in mind, it is a hard pill to swallow if you're using the max card size. more than that, some companies build into their plan the idea of flooding the market with so many games that the inevitable price drops are simply part of the deal. doing markdowns on switch games is a much more difficult experience because of card prices for those really big games.
that said, if kingdom hearts 3 is actually holiday 2019 like all of us rational people expect, then i think the switch is a good place for it. this is also like the wii's 2007 where publishers have a duty to themselves to get in on the platform while the iron is hot. after about 18 months, the direction will solidify and currently, it seems like japanese titles and throwback games are super in for switch fans. you probably won't see skyrim doing really well unless there are more games like it, but i expect stuff like a resident evil 2 remake, a final fantasy remake, and other older franchises will do well considering what's already succeeding.
also, unlike with the 3ds, the west is going to help determine the switch's future in a positive way. japanese developers looking for a bigger worldwide fanbase won't want to miss out.